Rebar Support Chair

ABSTRACT

A chair for supporting and spacing concrete reinforcement members having an integrally formed body including an upper receiving area and a lower base, where the receiving area includes a vertical fin defining an open notch for receiving a concrete reinforcement member. The receiving area may further include a gusset projecting from the vertical fin and extending upward to define a medial, lowest portion of the associated open notch. The vertical fin and gusset are adaptable such that chairs having different heights can be manufactured using a single molding apparatus.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/606,498, filed Jun. 26, 2003, the entirety of which shall beincorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates generally to chairs and spacers that areused in construction activities for the support of steel reinforcementmembers within concrete structures, and in particular to a stackablechair that reliably retains reinforcement bars, post-tension cables,rods, and the like.

2. Description of the Related Art

Chairs or spacers are commonly used in the construction industry for thesupport and positioning of steel reinforcement members such aspost-tension cables and/or reinforcement bars (“rebar”) a properdistance above a surface. Rebar is usually arranged in rows or gridswithin an area into which concrete is to be poured, and held loosely inplace while concrete is placed around it. In normal use, a receivingarea formed on the chair will contact and support the rebar while thebase of the chair rests on a deck or on a grade.

Proper spacing and arrangement of steel reinforcement members inconcrete slabs according to known engineering and architecturalspecifications impacts the structural strength and integrity of theconcrete structure. Such steel reinforcement requires sufficient coverto avoid exposing the steel to the effects of moisture-penetratingcorrosion. Once the steel is exposed to the effects of chemical-ladenmoisture, corrosion starts taking effect.

Known prior art chairs have desirable features which provide the propersupport of rebar or post-tension cables safely within a concretestructure. Some chairs also have additional desirable features. Forexample, U.S. Pat. No. 5,729,949 to Hartzheim discloses a readilystackable chair with a hollow-conical body that minimizes the amount ofshipping and storage space required. These chairs have support legs withapertures between them to allow concrete to flow into the hollowinterior of the chair. A worker can carry many chairs at one time andplace numerous chairs at a construction site without repeated trips to astorage area.

U.S. Pat. No. 6,089,522 to Haslem et al. discloses a stackable highchair having a lower base portion, an upper connecting portion and anupper support surface. The upper support surface includes bisectingcross members which join opposing corners of the upper support surface.Inclined ramps extend upwardly from the support surface and serve toposition the rebar along the upper surface. The upper support surfacealso includes a plurality of holes which allow a head piece to bemounted to the chair, thereby allowing the height of the chair to bereadily adjusted.

While the prior art chairs described above may be useful for theirrespective, particular objectives, a need exists for a stackable chairthat is tall enough to support rebar a significant distance above asurface, yet has a simple and strong construction. A further need existsfor an economical chair having a uniform base portion and an integralbut adaptable receiving area portion, such that a plurality of chairsproviding support at different heights may be manufactured using asingle molding apparatus.

BRIEF SUMMARY

Accordingly, one objective of the present invention is to provide achair with a simple yet strong design that is tall enough to supportrebar a significant distance above a surface. It is also an objective toprovide a tall chair that is light in weight yet able to securelysupport rebar. Yet another objective is to provide a tall rebar supportchair with a wide base that allows the chair to stand securely. It is afurther objective to provide a rebar support chair that can be stackedwithin another chair to provide a more efficient method for packaging,storage, and shipment. It is also a further objective to provide a rebarsupport chair including an integral receiving area that is adaptable forsupporting rebar at different heights above support surface yetmanufacturable using a single molding apparatus. Yet another objectiveis to provide a plastic chair made of durable, non-corroding materialsthat is easy to manufacture and easy to use.

Briefly stated, these objectives are accomplished by a generallyfunnel-shaped support chair having a hollow body with an inner surface,an outer surface, a receiving area, and a base. The base defines a loweropening and is adapted to rest on a planar support surface. Thereceiving area is adapted to receive and support the rebar. The loweropening of the chair is larger than the receiving area, and the innerand outer surfaces are substantially complementary to each other toallow a plurality of chairs to be stacked within each other for storageand shipment. Additionally, the stacking feature allows a worker tocarry a stack of chairs at the job site as he places them at desiredlocations.

In one aspect of the disclosure, the receiving area includes a first anda second pair of curved notches, with the second pair being orientedninety degrees from the first pair. The first pair of notches has afirst depth, and the second pair of notches has a second depth. Thefirst pair is deeper than the second pair, and the chair is thus able tosupport rebar at different heights and in perpendicular relationships toone another. The receiving area may optionally include a plurality ofbridges. A bridge is a band of material that spans the distance withinthe body of the chair between each of the pairs of notches. The bridgescan assist to further increase the supporting strength of the chair, andcan connect the medial, lowest portions, or troughs, of the notches.

In another aspect of the disclosure, the base includes a plurality ofsupport legs which define a plurality of apertures, and the aperturesallow poured concrete to pass fluidly through the chair. The aperturesare preferably arch-shaped, and the support legs preferably have athickened band of material around the apertures, such that the strengthof the chair is reinforced by these thickened areas to allow the supportlegs to be longer yet retain their strength. In one particular aspect,the base has four support legs, with two of the support legs furtherincluding foot members extending horizontally outwardly therefrom, theother two support legs lacking a foot member. In such an aspect, thefoot members extend from support legs which are diametrically opposedfrom one another. In another particular aspect, the base has foursupport legs, with adjacent support legs being joined by a horizontalstrut. In such an aspect, the horizontal struts collectively form aclosed, geometrically shaped hoop to prevent buckling or spreading ofthe support legs.

In another aspect of the disclosure, the base includes upper and lowersupport legs. The lower support legs are the primary set of legs and arelarger than the upper support legs. The receiving area is supported byboth the upper and lower support legs, with the upper legs extendingdownwardly from the receiving area, and the lower support legs extendingdownwardly from the upper support legs. In one particular aspect, theupper legs can include upwardly extending ribs on their outer surface.These ribs extend along each of the upper support legs between thejunction of the lower and upper legs. In such an aspect, the chair canbe made to be significantly taller than other chairs of the prior art,and also be light in weight yet strong enough to support rebar securely,and without collapsing under the weight of the rebar. Preferably thechair is advantageously manufactured as a single piece of material, suchthat the chair can have the height and strength of a chair having a headpiece seated on top of a base chair, yet be a single, tall chair withtwo sets of support legs.

In accordance with another aspect of the disclosure, the body of thechair has multiple substantially straight sides and a substantiallysquare cross-section having rounded corners, with an inner surface thatis complementary to the outer surface to allow a plurality of chairs tobe stacked together, one inside the other, for storage and shipment. Thechair may also have an elliptical, oval or hybrid cross-section. Thechair preferably has a wide base which is adapted to rest on a flatsupport surface. The lower opening is defined by the base and ispreferably larger than the upper receiving area, and the inner and outersurfaces are preferably substantially complementary to each other.

In accordance with another aspect of the disclosure, a chair includes anadaptable receiving area having a vertical fin defining an open notch.The receiving area of the chair also preferably includes a gussetprojecting perpendicularly from the vertical fin and extending upward tofurther define the medial, lowest portion of the notch. In oneparticular aspect, the receiving area of the chair includes fourvertical fins defining a first and a second pair of opposed opennotches, with first and second pairs of notches being oriented at ninetydegrees from each other. The medial, lowest portion of the first pair ofnotches is located at a lower height than the corresponding portion ofthe second pair of notches, and the chair is thus able to support rebarat different heights and in perpendicular relationships to one another.Preferably, the receiving area also includes a gusset projectingperpendicularly inward from each vertical fin and extending upward tothe medial, lowest portion of each notch to further increase thesupporting strength of the vertical fins. In another particular aspect,the receiving area of the chair includes one vertical fin defining anopen notch, and a pair of gussets projecting perpendicularly outwardfrom the vertical fin and extending upward to the medial, lowest portionof the notch to both increase the supporting strength of the verticalfin and provide a resistance to tipping.

In accordance with another aspect of the disclosure, the receiving areaand the base are integrally formed together from a durable,non-corroding polymeric material. The chairs are easy to manufacture inthis fashion, and packaging and storage of the chairs can be donequickly and easily because the chairs are also stackable. These andother aspects of the disclosure will be more fully appreciated withrespect to the following drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one aspect of a chair;

FIG. 2 is a perspective view of the chair of FIG. 1 in which rebar hasbeen placed in the receiving area;

FIG. 3 is a perspective view of another aspect of a chair having twosets of support legs;

FIG. 4 is a perspective view of a plurality of chairs of FIG. 1 stackedwithin one another in accordance with one aspect of the disclosure;

FIG. 5 is a perspective view of a plurality of chairs of FIG. 3 arrangedin a stack;

FIG. 6 is a perspective view of one aspect of a chair having anadaptable receiving area including vertical fins;

FIG. 7 is a perspective view of another aspect of a chair havingvertical fins, illustrating the adaptability of the receiving area;

FIG. 8 is a perspective view of another aspect of a stackable chairhaving vertical fins and horizontal struts;

FIG. 9 is an elevational cut-away view of a mold for manufacturing achair having an adaptable receiving area including vertical fins.

DETAILED DESCRIPTION

Referring now to FIG. 1, a perspective view is shown of one aspect of achair 8 having a hollow body 10 including a base 12, a receiving area14, an inner surface 16, an outer surface 18, and ribs 20 formed on theouter surface for a purpose described below. The base 12 defines a loweropening 22 and is adapted to rest on a planar support surface. Thereceiving area 14 has a plurality of generally rounded notches 24, withelevated notch junctions 26 between adjacent notches. The lower base 12has a plurality of separate support legs 32 extending downwardly fromthe receiving area 14. Foot members 34 extend radially outward from twoopposing support legs 32. Adjacent support legs 32 define holes orapertures 36, which allow poured concrete to fluidly pass through thechair 8. The legs 32 have a thickened band of material 40 around eachaperture 36.

The chair of FIG. 1 is preferably generally square in cross-sectionhaving rounded corners and is constructed of a single piece of resilientpolymeric material. However, alternative aspects of the chair may have apolygonal, elliptical, oval or hybrid cross-section. The receiving area14 is adapted to receive and support concrete reinforcement members, orrebar. The inner surface 16 is complementary to the outer surface 18,and the body 10 has multiple straight sides and is generally tapered,with the lower opening 22 being larger than the receiving area 14,thereby allowing multiple chairs to be stacked within one another forstorage and shipment. The tapered shape of the chair also requires thatthe upper portion of the body 10, including the receiving area 14, isgenerally relatively narrow as compared to the lower portion, whichincludes the wider base 12. Ribs 20 function to space stacked chairs andfacilitate their separation.

The apertures 36 between the support legs 32 are preferably arch-shapedand allow fluid concrete to pass through the body 10 beneath the levelof the receiving area 14. The large openings provided by the apertures36 maximize the free flow of concrete into and around chair 8. Thesupport legs 32 preferably have a thickened band of material 40 aroundthe apertures 36, such that the strength of the chair is reinforced bythese thickened areas 40 to allow the support legs 32 to be longer yetretain their strength. As shown, the base 12 has four support legs 32,with two of the support legs further including foot members 34 extendinghorizontally outwardly therefrom, the other two support legs lacking afoot member. In FIG. 1, the foot members 34 extend from support legs 32which are diametrically opposed from one another.

FIG. 2 shows reinforcement members 38 and 39 being supported by thechair 8 of FIG. 1. Reinforcement members 38 and 39 intersect with oneanother within the receiving area 14. The receiving area 14 includes afirst and a second pair of curved notches, 24 a and 24 b, respectively,with the second pair 24 b being oriented ninety degrees from the firstpair 24 a. The notches 24 a, 24 b comprise curved bearing surfacesextending inwardly from outer surface 18. The first pair 24 a are deepnotches which receive rebar member 38, and the second pair of notches 24b are shallow notches which receive rebar member 39, such that rebarmember 39 is situated above and perpendicular to member 38 within thereceiving area 14. The chair 8 is thus able to support rebar members 38and 39 both at different heights and in perpendicular relationships toone another.

As a non-limiting example of how the reinforcement members 38 and 39 areplaced within the chair 8, reinforcement member 38 is initiallypositioned over the receiving area 14 and then lowered into the deepnotches 24 a. Reinforcement member 39 is then lowered into the shallowpair of notches 24 b. Notch pairs 24 a are preferably deep enough toallow reinforcement member 38 to sit within the receiving area 14 whilealso allowing member 39 to sit completely within the shallow notch pairs24 b without interference from member 38.

FIG. 2 further illustrates the tapered shape of the chair 8. The upperportion of body 10 is narrow at the receiving area 14. The body 10gradually widens from the notch junctions 26 down to the ends of thesupport legs 32. The lower opening 22 is therefore much larger incircumference than the receiving area 14. Also, each support leg 32proceeds downwardly in a straight line from a junction 26. Preferably,two of the support legs 32 have a foot member 34 extending horizontallyoutwardly therefrom, adding further support to the base such that thebase is well adapted to support the weight of the chair 8 as well as thereinforcement members 38, 39.

FIG. 3 illustrates another aspect of the chair 108 in which the base 112includes both lower 132 and upper 133 support legs. The lower supportlegs 132 are the primary set of legs and are larger and longer than theupper support legs 133. The receiving area 114 is supported by both theupper and lower support legs 132, 133, with the upper legs 133 extendingdownwardly from the receiving area 114 and defining upper apertures 137,and the lower support legs 132 extending downwardly from the uppersupport legs 133 and defining lower apertures 136. A ledge 142 definesthe junction between the upper 133 and lower 132 legs, and can be seenextending around the circumference of the body 110.

As shown in FIG. 3, the base 112 has four lower support legs 132, withtwo of the lower support legs 132 further including foot members 134extending horizontally outwardly therefrom, the other two lower supportlegs lacking a foot member. The foot members 134 extend fromdiametrically opposed lower support legs 132. Upwardly extending ribs120 are disposed on outer surface 118 and act as spacers to facilitateseparation of stacked chairs, as described above with respect to ribs 20of FIGS. 1 and 2.

The lower and upper apertures 136, 137 between the lower and uppersupport legs 132, 133, respectively, are preferably arch-shaped andallow fluid concrete to pass through the body 110 beneath the level ofthe receiving area 114. The large openings provided by the apertures136, 137 maximize the free flow of concrete into and around chair 108.The lower support legs 132 preferably have a thickened band of material140 around the lower apertures 136, such that the strength of the chairis reinforced by these thickened areas 140 to allow the lower supportlegs 132 to be longer yet retain their strength.

The receiving area 114 shown in FIG. 3, similar to the receiving area 14in FIGS. 1 and 2, is adapted to receive and support concretereinforcement members, or rebar. The inner surface 116 of the base 112and receiving area 114 is complementary to the outer surface 118, andthe body 110 has multiple straight sides and is generally tapered, withthe lower opening 122 being larger than the receiving area 114, therebyallowing multiple chairs to be stacked within one another for storageand shipment. Advantageously, the stackable chairs 108 facilitatehandling on a job site, whereby workers may carry a stack of chairs 108in one hand while placing individual chairs from the stack at desiredlocations at the job site.

The receiving area 114 of FIG. 3 further includes a plurality of bridges128. A bridge junction 130 is formed where two bridges 128 meet in thecenter of the receiving area 114. The bridges 128, which are shown herebut are an optional element of the chair 108, connect the medial, lowestportions, or troughs, of the notches 124, and span the distance withinthe body 110 of the chair between the notches 124. The bridges 128assist to further increase the supporting strength of the chair 8. Thebridges 128, which are optional, serve to support the rebar members 138and 139 as they traverse the body 110 of the chair, and add strength andsupport to the structure.

Apertures are shown in FIGS. 1 through 3 as being generally arch-shaped,curved at the apex. One of skill in the art will recognize, however,that a variety of shapes, sizes, and numbers of apertures can be used.Support legs are generally of sufficient width and strength to support asubstantial load, such as the force of the reinforcement members as wellas the force applied by construction workers who may step or walk on thereinforcement members during the construction process. The thickenedband of material around the apertures also adds strength to thestructure, so that the chair does not collapse under such weight. Eachfoot member allows the base to rest on a flat, planar support surface,including loose or pliant surfaces such as dirt, sand, or the like.

As illustrated in FIG. 4, a plurality of chairs 8 a and 8 b can bestacked together, one inside the other, for packaging, storage andshipment. The combination of the tapered, generally funnel-like shape ofchairs 8 a and 8 b, along with the complementary surfaces, allows theupper receiving area of chair 8 a to be inserted within the loweropening 22 of chair 8 b, such that the outer surface 18 a of the firstchair slidably engages the inner surface of the second chair. Thedistance that a first chair is able to fit inside a second chair isdependant upon the degree of slope assumed by the surfaces 16 and 18 asthe body 10 progresses from the receiving area 14 to the lower opening22. That is, the smaller the receiving area is relative to the loweropening 22, the greater the slope will be of the surfaces 16 and 18.Preferably, this slope is sufficient to allow a substantial portion ofthe first chair to fit within the second chair, such that a great numberof chairs can be stacked in a minimal amount of space without the stackbecoming too tall or burdensome. As noted above, ribs 20 space stackedchairs and facilitate their separation.

As shown in FIG. 5, the chairs shown in FIG. 3 can be similarly stackedwith the foot members of one chair on opposite support legs as the footmembers of the preceding chair, or alternatively the foot members can beon the same corresponding support leg, such that a user can recognize aspecific corner of the chair. It will be apparent that the stackingcapability allows a workman to carry a stack of chairs with one hand ashe places chairs at the job site.

Referring now to FIG. 6, a plurality of chairs 208 similar to the chairshown in FIG. 3 may be manufactured by combining a base 212 with anadaptable receiving area 214. The base 212 may be generally identical tothe base 112 described previously, with similar reference numerals usedto indicate similar structure, e.g., lower 232 and upper 233 supportlegs. The base 212 may also be generally identical to the base 12described previously, the relevant characteristic being that the baseportion or body of the chairs 208 is essentially uniform with regard toboth size and structural design. The adaptable receiving area 214 mayinclude four vertical fins 250 defining a first 224 a and a second 224 bpair of opposed open notches. The term “vertical fin” as used hereinshall mean a vertically projecting structure having uniform lateralextents, and include structures providing stepwise and/or progressivelyexpanding voids defined within such extents. The term “open notch” asused herein shall mean that the space directly above the entirety of thenotch feature is free from obstructions such as overhangs, latchingprojections, or other means for impeding the vertical movement of rebar,post-tension cable, and the like away from the notch. The inner surface216 of the base 212 is generally complementary to the outer surface 218,with a lower opening 222 being larger than the receiving area 214,thereby allowing multiple chairs to be stacked primarily within oneanother for storage and shipment. The vertical fins 250 will spacestacked chairs and facilitate their separation, such that ribs 20, 120may be omitted.

The first pair of notches 224 a and the second pair of notches 224 b areoriented at ninety degrees from each other, with the medial, lowestportion, of the first pair of notches 224 a being located at a lowerheight than the corresponding portion of the second pair of notches 224b. Thus, a single chair 208 may support rebar at different heights andin perpendicular relationships to one another. For example, a chair 208may support a single portion of rebar at one of two heights above asupport surface, e.g., at 5.25″ or at 5.5″ above grade, or support arebar grid in an overlapping, perpendicular relationship, e.g., at 5.25″and 5.5″ above grade.

The receiving area 214 of a plurality of chairs 208 is adaptable suchthat different chairs 208 may provide support at different heights abovea support surface yet be manufacturable using a single moldingapparatus. The receiving area 214 is adapted by altering the length ofthe vertical fins 250 to vary the height of the medial, lowest portionof the notches 224. For example, a second chair 208 having longervertical fins 250 but an essentially identical base 212 may support asingle portion of rebar at one of two other heights above a supportsurface, e.g., at 5.75″ and 6.0″ above grade, such that two slightlyvarying chairs 208 may manufactured which collectively offer support forrebar at four differing heights above a support surface. Advantageously,altering the manufactured length of the vertical fins 250 permits asupplier to produce a line of such varying chairs using a single moldingapparatus, as described below.

In aspects such as the one described above, each vertical fin 250 ispreferably reinforced by a perpendicular gusset 252 projecting inwardlyfrom the vertical fin 250 and extending upward to further define themedial, lowest portion of the associated notch 224. The gusset 252increases the supporting strength of the vertical fin, preventing bothlateral deformation and localized crushing of the fin by rebar,post-tension cable, and the like that is received in the notch. Themanufactured length of the gussets 252 may also be altered to permitproduction of varying chairs using a single molding apparatus.

FIG. 7 illustrates another aspect of a chair 308 combining a generallycruciform body 310 including four support legs 332 with an adaptablereceiving area 314. Two opposing support legs 332 may configured asprojections extending laterally and downward from a vertical fin 350defining an open notch 324. Two other opposing support legs 332 may beconfigured as projections extending laterally and downward from a pairof opposing gussets 352 projecting perpendicularly outward from thevertical fin 350. The gussets 352 both extend upward to further definethe medial, lowest portion of the notch 324, and to increase thesupporting strength of the vertical fin. Such gussets 352 may alsoprovide a resistance to tipping by reducing the tendency of rebar tocatch on the edges of the open notch 324, and by repositioning a rebar'sapplied weight toward that portion of the chair 308 having a tendency torotate upward in response to a longitudinal movement of the rebar.

FIG. 8 illustrates yet another aspect of a chair 408 combining a body410 with an adaptable receiving area 414. The body 410 has a pluralityof support legs 432 extending downwardly from the receiving area 414.Each leg 432 is joined to adjacent legs 432 by a horizontal strut 444,and the horizontal struts 444 collectively form a closed, geometricallyshaped hoop 446 to prevent buckling or spreading of the legs 432.Adjacent support legs 432 define holes or apertures 436, which allowpoured concrete to fluidly pass through the chair 408. The legs 432 mayalso have a thickened band of material around each aperture 436, suchthat the legs 432 have a T-shaped or cruciform profile (not shown). Thelegs 432 and horizontal struts 444 jointly define a lower opening 422.The body 410 is generally tapered, with the lower opening 422 beinglarger than the receiving area 414, thereby allowing multiple chairs tobe stacked primarily within one another.

The receiving area 414 includes a vertical fin 450 defining an opennotch 424 and a pair of opposing gussets 452 projecting perpendicularlyoutward from the vertical fin 450. The gussets 452 may each extendupward to further define the medial, lowest portion of the notch 424.The gussets 452 increase the supporting strength of the vertical fin,and may also provide a resistance to tipping by reducing the tendency ofrebar to catch on the edges of the open notch 424, and by repositioninga rebar's applied weight toward that portion of the chair 408 having atendency to rotate upward in response to a longitudinal movement of therebar. With particular reference to the structure shown in FIG. 8, twoof the opposing support legs 432 may be projections extending laterallyand downward from the vertical fin 450, and two of the other opposingsupport legs 432 may be projections extending laterally and downwardfrom the opposing gussets 452.

In aspects such as the one described above, when multiple chairs arestacked, interference between the legs 432 of one chair 408 and the hoop446 of a second chair 408 will substantially constrain horizontalmovement of the bottom of the second chair 408. The efficiency of suchstacking will vary depending upon the length of the vertical fin 450,but still permit storage and shipment within a reduced volume, and stillpermit a worker to carry many chairs at one time at a construction site.

As discussed above, altering the manufactured length of the verticalfins 250, 350, 450 permits a supplier to produce a line of chairsproviding support at different heights using a single molding apparatus.Referring now to FIG. 9, a mold 500 may be formed, shaped, or otherwisemanufactured to provide a mold cavity having the basic configuration ofa chair, e.g., chair 208, including the body 210, 310, 410 and receivingarea 214, 314, 414 but excluding any vertical fins 250, 350, 450otherwise included in the receiving area. The mold may further includeor subsequently be modified to include a first channel 510 having across-section corresponding to the cross-section of a first vertical fin250, a second channel 510 having a cross-section corresponding to thecross-section of a second vertical fin (if present), etc.

The mold may also include a first adjustable blade 520 having across-section corresponding to the cross-section of the first verticalfin 250, a second adjustable blade 520 having a cross-sectioncorresponding to the cross-section of the second vertical fin (ifpresent), etc. Each adjustable blade 520 may be fully inserted into itscorresponding channel 510 such that the inserted end 525 of the blade520 defines a top surface of the notch in the receiving area of thechair. However, each adjustable blade 520 may also be partiallywithdrawn into its corresponding channel 510 such that material mayenter the channel 510 to form a vertical fin 250, with the inserted end525 of the blade 520 defining a top surface of the notch 224 in thevertical fin 250. By adjusting the insertion of each blade 520, asupplier may adjust the length of the vertical fins 250, 350, 450 in achair to produce a plurality of chairs providing support at differentheights above a support surface using a single molding apparatus.

In aspects where gussets 252, 352, 452 are present, the mold may includea channel 510 and blade 520 having cross-sections corresponding to thecross-section of the vertical fin 250, 350, 450 and the associatedgusset(s) 252, 352, 452. The inserted end 525 of the blade 525 willconsequently further define the top surface of the associated gusset(s)252, 352, 452 and preferably further define the structure associatedwith the medial, lowest portion of the notch 224, 324, 424.

The chairs disclosed herein can be made significantly taller than mostchairs of the prior art, and are also light in weight yet strong enoughto support rebar securely, without collapsing under the weight of therebar. Preferably the chairs are advantageously manufactured as a singlepiece of material, and constructed from a resilient polymeric materialand, more specifically, constructed of a plastic or resin material. Inthis manner, the chairs can have the height and strength of a chair witha head piece seated on top of a base chair, yet be a single, tall chair.Further, the chairs are most preferably made of polypropylene and areone-piece injection molded. One of ordinary skill in the art willrecognize that other materials exhibiting similar characteristics ofbeing lightweight, strong and resilient can be used, such aspolyethylene, a combination of polypropylene and polyethylene, and otherknown materials.

The present invention has been disclosed in detail in connection withthe preferred embodiments. While there are many modifications that canbe made without departing from the scope of the present invention, thepresent invention is defined by the claims that follow.

1. A chair for supporting and spacing concrete reinforcement members,comprising: an integrally formed body including an upper receiving areaand a lower base, the receiving area including a vertical fin definingan open notch for receiving a concrete reinforcement member, and thebase adapted to rest on a planar support surface.
 2. The chair of claim1, wherein the receiving area further includes a gusset projecting fromsaid vertical fin.
 3. The chair of claim 2, wherein the gusset extendsupward to further define a medial, lowest portion of an associated opennotch.
 4. The chair of claim 2, wherein the receiving area includes apair of opposing gussets projecting perpendicularly from the verticalfin.
 5. The chair of claim 4, wherein the base includes four supportinglegs, with two of the legs being projections extending from the verticalfin.
 6. The chair of claim 4, wherein the base includes four supportinglegs, with two of the legs being projections extending from the opposinggussets.
 7. The chair of claim 1, wherein the receiving area includesfour vertical fins defining two pairs of diametrically opposed opennotches, the medial, lowest portions of the first pair of opposed opennotches being located at a different height above the support surfacethan the medial, lowest portions of the second pair of opposed opennotches.
 8. The chair of claim 7, wherein the receiving area furtherincludes a gusset projecting inwardly from each vertical fin.
 9. Thechair of claim 8, wherein each gusset extends upward to further define amedial, lowest portion of an associated open notch.